Susan G. Komen® hailed new findings released today at the San Antonio Breast Cancer Symposium by Roche from their KATHERINE clinical trial that shows patients with early stage HER2+ breast cancer who used T-DM1 (Kadcyla®) following surgery rather than Herceptin®, which is the current standard of care, are at lower risk of recurrence or death at 3 years after treatment.

“The KATHERINE trial will have an immediate clinical impact for patients with aggressive HER2-positive early stage disease. This is a real win for our patients, and further evidence for the importance of randomized controlled trials in defining new standards of care for breast cancer patients,” according to Chief Scientific Advisor, George Sledge, Jr., M.D., Professor of Medicine and Pathology, and Chief of the Division of Oncology in the Department of Medicine at Stanford University.

KATHERINE tested if T-DM1 would be a more effective treatment after surgery (adjuvant treatment) for patients than the standard of care, trastuzumab (Herceptin®). This trial was an international, multi-center, two-arm, open-label, randomized Phase III study comparing these 2 targeted therapies following surgery in patients with HER2+ early stage breast cancers. The drug T-DM1 is the antibody trastuzumab, that targets HER2, attached to a second drug, emtansine (DM1). Trastuzumab recognizes tumor cells with HER2 and blocks it, but with T-DM1, the drug also delivers a chemotherapy drug that helps to kill the tumor cells directly. This antibody-drug conjugate ideally limits damage to healthy cells by delivering the chemotherapy directly to the cancer cells with HER2. This combination was shown to improve outcomes in early stage, HER2 + patients who still had invasive cancer after pre-treatment (neo-adjuvant treatment) when they went in for surgery.

Patients often receive treatment prior to surgery with the goal of shrinking the tumor. Those who receive treatment prior to surgery and who still have residual disease after that treatment have worse outcomes than those who do not have any obvious disease. These patients are often given treatment after surgery (adjuvant therapy) to reduce risk of recurrence. In this study, patients with residual disease who were treated with T-DM1, showed that 88.3 percent of patients at three years did not have their breast cancer return compared with 77 percent for patients treated with trastuzumab alone. Invasive disease occurred in 22.2 percent of patients treated with trastuzumab and in 12.2 percent of those receiving T-DM1, reflecting a 50 percent reduction in the risk of recurrence.

Komen is committed to improving outcomes for metastatic and aggressive cancers. As part of the organization’s Bold Goal to reduce the current number of breast cancer deaths in the U.S. by 50 percent by 2026, this year Komen focused about 70 percent of its research funding into metastatic breast cancer and treatment resistance.